Modular conveyor systems using standardized uniform stock components normally of extruded material are well known in the art. Modular conveyor systems have an advantage in that they can be assembled in the field whereas customized systems are typically factory assembled and shipped to the operating site. In addition, use of standardized modular components allows a conveyor system to be designed for a particular layout without having to custom design special components such as conveyor beams, side rails, chains, fasteners and bracketry. However such prior art modular conveyor systems still require some labor intensive steps for assembly such as, for example, bolting the side rails to the conveyor beam along longitudinally extending "T-slots" in the beam. The use of such construction increases cost, complexity of manufacturing and installation. An additional problem with modular conveyors of such conventional construction is the tendency for foreign material to accumulate in various slots and interfaces associated with the fittings and surfaces to receive the standardized components. Consequently, washdown of such conveyor systems can be problematic, particularly for the food industry.
For example, U.S. Pat. No. 3,800,938 (Stone) discloses a conveyor assembly comprising an elongated pair of oppositely disposed extrusions forming a pair of "T slots" or channels. Part of the extruded frame is inclined to allow contaminants to roll off the beam, thus providing a form of self-cleaning. However, an extruded frame assembly with such T slots is more costly to manufacture and has the problem of greater accumulation of debris on the conveyor assembly due to the formed channels or grooves. Moreover such grooves pose alignment problems and are subject to imperfections and damage such as bending.
U.S. Pat. No. 4,146,126 (Mattos) discloses a modular conveyor using a plurality of pedestals arranged along a single line removably connected to a plurality of aligned beams. Although the conveyor can be adjusted to open the belt for interior cleaning, the unit comprises a more complex design involving at least two idler rollers and a subframe pivoted between side rails. Such an assembly is costly to manufacture and maintain and requires more bolting and brackets to achieve a modular assembly.
U.S. Pat. No. 4,961,492 (Wiseman, et al.) teaches the use of an "H-shaped" core beam member wherein the beam also has at least four extruded channels running the length of the beam. The disclosed conveyor allows the chain to be relatively freely removed from the H beam to facilitate maintenance and cleaning. However, the H beam can be more costly to manufacture and assemble, and there is no provision for mounting article guide rails in a modular fashion that is integral to the design of the conveyor assembly as disclosed.
U.S. Pat. No. 5,082,108 (Douglas) teaches a modular conveyor beam with a plurality of cross members with tongue and groove combinations on opposing lateral sides, as well as a pair of opposing side guides with such a tongue and groove combination. The side guides must fit in a tongue and groove channel formed along the entire length of the beam assembly thereby increasing the cost of extruding the beam member and side rail.
U.S. Pat. No. 5,178,263 (Kempen) teaches the use of a modular track unit using a horizontal "I shape" beam. As with the other prior art, each side of the track includes a longitudinal slot running the length of the beam. In addition to the other disadvantages mentioned in the previous patents, such a subunit does not readily allow for the use of curves in the conveyor assembly as the function of the side stiffening rail is to promote further support of the guide beam assembly. Moreover, the conveyor assembly requires numerous bolted connections and provides no means to easily adjust the position of guide rails to accommodate various sized articles for conveying.
U.S. Pat. No. 5,316,134 (Donohue) discloses an elongated frame made up of a number of extruded guide track segments, including a pair of vertical side walls extending top to bottom along the entire length of the beam assembly. Such a design still allows increased opportunity for foreign matter and debris to accumulate due to numerous extruded guide track segments. This renders cleaning more difficult and manufacturing more costly due to the extra material and tolerances associated with forming numerous guide track segments. In addition, as with the Kempen patent, the conveyor assembly is not designed to easily adjust the position of guide rails to accommodate various sized articles for conveying as the rails are bolted to brackets, which in turn are bolted to the side walls of the elongated frame.
A disadvantage to the prior art is that previous designs of modular conveyor assemblies either employ a design that is more costly and complex, or are not of a construction that allows for ease of assembly and cleaning. What is desired, therefore, is a modular conveyor beam assembly that is less costly to manufacture, easier to assemble, configure and dismantle, and is of a design that facilitates cleaner operation by using less exposed surfaces.